Intel (INTC) shares this morning are weighed down by not just a broadly weak market -- the Nasdaq Composite Index is off 0.6% -- but also a couple of dour sell-side reports. The stock is down 50 cents, or 2%, at $24.33.

Piper Jaffray's chip analyst Gus Richard this morning reiterates a Neutral rating on shares of Intel, and a $23 price target, writing that the "Post-PC era surfaces," based on his expectation that a raft of computing devices will prove to be winners this holiday era, further ending the "Wintel" era of computing, meaning the combination of Intel's chips and Microsoft's (MSFT) Windows software that dominated PC computing.

Richard ticks off the non-Intel devices he expects to thrive, from Apple (AAPL), Amazon.com (AMZN), and Google (GOOG), among others, which culminates, in his view, with the "Surface" tablet computer Microsoft has designed (though, mind you, one of the models of surface runs on an Intel processor):

Nexus 7, Kindle Fire, Microsoft Surface and iPad Mini. These ARM-based products are likely to be priced between $199-$299. This is less than half the price of a low-end Ultrabook at $600. Moreover, given the Surface will run Office, it eliminates the last major hurdle, in our view, in adopting a tablet.

Richard sees Intel struggling to match prices of chips for the non-Wintel devices, including chips from competitor Nvidia (NVDA), based on the technology licensed to Nvidia and others by ARM Holdings (ARMH):

We estimate NVDA's ARM-based processor used in Microsoft's Surface tablet is priced in the range of $15-$20 and potentially lower, based on our checks. This 1/5 to 1/10 the cost of a notebook CPU from Intel. This lower ASP, along with Microsoft's willingness to sell hardware near its manufacturing costs to proliferate its OS, should allow MSFT to sell the Surface for ~$199 or 1/3 a low- end Ultrabook. In our view, a $199 tablet that runs Microsoft Office is going to be a very compelling alternative to an Ultrabook or regular notebook. We believe without the Wintel hegemony, Intel either has to lower prices aggressively and/or face steadily declining revenue as the notebook market shrinks over the next couple of years.

Richard also sees tablet computers shipping in higher volume than notebook computers by the second half of next year:

We believe tablets out-ship notebooks in 2H:CY13. This assumes that notebooks decline by 2% this year and 8% next year as the proliferation of low cost tablets continues and conversion to ARM accelerates with Window RT and MSFT's Surface. We think this conversion is driven by the availability of Microsoft Office on ARM and the inherently lower cost and margin of the Surface CPU. We think at this point there is little Intel can do to protect its legacy notebook business.

Also today, market research firm IHS iSuppliweighed in on the end of Wintel, projecting processor and operating system share declines for both Microsoft and Intel:

Despite a flurry of activities to adjust to the changed realities of the technology industry, Wintel is expected to suffer a declining share of the "new" computer market, a category consisting not just of PCs but also of the much faster-growing smartphone and media tablet segments. Microsoft's share of the operating system market for the three products combined is expected to slip to 33 percent in 2016, down from 44 percent in 2011, according to an IHS iSuppli DRAM Dynamics Report from information and analytics provider IHS. Meanwhile, Intel's share of microprocessors will fall to 29 percent, down from 41 percent. At the same time, the total size of the market will double from 2011 to 2016, almost entirely due to the strong growth of the smartphone and media tablet segments, as presented in the table below.

In a similar vein, Credit Suisse's John Pitzer this morning reiterates an Outperform rating, but cut his estimates for Intel for this year and next, citing "the continued macro weakness impacting PC demand."

But it's more than simply lackluster PC sales: Like Richard, Pitzer is concerned that a structural change as tablet computers gain prominence and the "ultrabook" laptops Intel is pushing struggle to reach attractive price points:

PC weakness will impact growth over the next two quarters. We view these issues as transitory BUT concede that over the next 3-4 months the STRUCTURAL BEAR call will likely GAIN momentum. There are four issues in the NT: 1) wallet share with iPhone5 and iPad mini launches in Sept/Oct., 2) what we expect to be a highly subsidized WinRT Surface launch from MSFT, 3) lack of availability of touch- based Ultrabooks at volume price points at Win8 launch, and 4) emerging market GDP which continues to decelerate.

Pitzer cut his 2012 revenue estimate to $54.6 billion from a prior $56.2 billion, and cut his EPS estimate to $2.25 from $2.45. That is below the Street consensus for $55.7 billion and $2.39.

While Pitzer also cut this quarter's estimate to $13.89 billion and 56 cents from a prior $14.3 billion and 61 cents, he doesn't think Intel will necessarily need to pre-announce the quarter. Consensus is at $14.23 billion and 60 cents, while Intel's own forecast for revenue was for $13.8 billion to $14.8 billion.

Richard's and Pitzers's concerns are consistent with a discussion among several analysts last week as to whether Intel will pre-announce. However, they stand in contrast to the downgrade of ARM Holdings this morning by Deutsche Bank's Kai Korschel, in which he warns that Intel will become increasingly competitive next year with advances in process technology for making chips at smaller geometries.

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